Since after a while arena gets pretty stagnate, I propose a city buff or guild tech buff that increases the stakes you receive in arena. Now of course this would not apply to leader cards or 1k gems. But I am level 88 and the big coin gives me about 206k coins. That's not a lot to be honest at this stage in the game. Now stakes do increase as your level goes up, but not proportionally IMO. If we had a guild tech that could increase the coins and credits you receive in arena 20% per level, that would make arena stakes more useful later in the game.